Pneumatic tool for cleaning switch banks



July 8, 1952 v. F. MILLER PNEUMATIC TOOL FOR CLEANINGISWITCH BANKS s Sheets-Sheet i Filed Dec. 19, 1946 INVENTOR M E MILLER AT TORNEV July 8, 1952 v, MlLLER 2,602,180

\ PNEUMATIC TOOL FOR CLEANING SWITCH BANKS Filed DEC. 19, 1946 3 Sheets-Shae} 2 a H6. 7 1 45* f Ag: 1 i 56 I 4/ 47 ATTORNEY V. F. MILLER PNEUMATIC TOOL. FOR CLEANL ENG SWITCH BANKS July 8, 1952 3 Sheets-Sheet 3 Filed Dec. 19, 1946 )NVENTOR 14 E MILLER aam A T TORNEV Patented July 8, 1952 UNITED STATES PATENT OFFICE PNEUMATIC TOOL FOR oLEANrNei SWITCH BANK-S Victor: F. Miller. Queen Villa-ge N. ,Y..,- assignor to Bell Telephone. Laboratories, Incorporated..- New York, N. Y acorporation of New York Application December 19, 1946; Serial No. 717,180

3 Claims.- (Cl. 151-339).

This invention relates to..a..machineforremov ings. coatings of preservative and protective substances previously applied to. electrical. terminals and. is. more specifically 'related to a machine for removing such substances: as. petrolatum from. terminals of panel telephone switching system terminal banks "Heretoiore. ithas been kncwnthat switching apparatus terminals included in telephone talking: circuits impose: undesirable: noise into these circuitsby virtue of the unstable contact resistance thereof caused largely by tarnish-anddirt accumulations on the; terminals. Theprioyart hasxmettheaproblem byapplying suchsubstances as."Vaseline,. commonly knownas petrolatum', to. the terminalsin mixture with small amounts of: other: substances to control the flow and abrasive properties of the composite mixture. Theapplication of this :compound'to the terminalsr prevents. oxidizing agents from creating tarnish.v thereon and inhibits accumulation of. globules or balls. of dirt and. link, etc. at the: contacting area. of same. Various methods of. applying: the -:compound have been used. and variousamachinesihave been employed toperform-the: tasks.

Prior: to the: advent oi. the present invention, thezmethodsiof and machines piorremoval of;said: compound. after its useful lifeof-perhaps oneand oneehaltito. two years; have been unsatisfactory for anumber; ofreasons. Such machine are exemplifiedby combs and. washing brushes whereby the;compoundxhas.been combed .or'washed orv brushed from the terminals; The use-ofsuch machines and methods have not eificiently re;- moved all of the compound norihave they. done so quickly and without attendant somewhat uncontrolled dirty conditions not to mention re-.- quirement of skill in so usin them.

It is, therefore, the object of the presentinvention to provide a tool which .will efliciently and effectively remove petrolatum or similar compounds irom the bank terminals of switches with aminimum of deleterious effects and without-requiring the servicesof askilled operator.

Toattain this object the present invention com-prisesa removing tool having a chamber for receiving the compound removed from the terminals, a special nozzle end adapted to engage the terminals, and means'for employing heatedair under pressure to force the compound from the terminals into the said chamber by virtue of the special construction of the said special end. The exhaust products are filtered and theused comcompound on theterminalsin a short timeand does: not require a skilled operator to operate sameemciently. Theeremoved compound is confined. to closed passageways and chambers in the. toolfrom the instant itis swept from thete-rminalsby; the heated air. Theonly exhaust product which: is expelled. into the space ambient'to the operator and' switching equipment. is air which has. been decontaminated: by having been filtered through. activated carbon subsequent to having; beenused to forcecompound from the termirmls.

In general a containeris provided which houses absorbent material suchas cotton or the like and activated carbon. The container is provided with a handle and means forattachingto. said container ran air'zhose and electrical wires. Also attached totsaidzcontainer are two passageways, such aspipeg or' similar devices, both f. which are. terminated in a common end head for the. tool. Thisend-heachv or-airdirecting structure as it: will be'referred to. at various times herein, comprises-a cylindricalbody: member of special constructions and a thimble. or deflecting. assembly. over the. end thereof, both housed in a'suit able: insulating. guide. member which generally may-beaconsidered aspart of saidend head structure-.: Therguideemember. is adapted to engage a row of terminals-from which itis vdesired to remove. compound.: The body. member and thimble arrangement is supplied. with airunder pressure fromtheraforementioned; air hose after said-air. has. been heated. by; passing; through or around an electrical :heatingelement housed in one ofthe pipes; or. passageways. The. air directing; structureireverses the..--direction: of theheated air and forces same acrosslthe terminals, the pressure ofsaid air; blast .forcingthe compound back-into the: container where the-used compound is absorbed'lby the-cotton and the contaminated air is filteredztthrough activated carbon and exhausted into .the .ambient'space;

Hereinafter: is :setiorth: av detailed description of. a'ipreferredrembodiment of the invention with the assistance of .thedrawings, of which:

Fig llillustrates .acut=awayrelevationviewiofi a preferred embodiment .'of my invention in operational position. with a panel system terminal bank;

Fig; zlishowsazplan view ofthe forwardor head end of the tool=shown'in'Fig;. l; V

Fig. 3 is a section taken along-the line 3 -*3 o-I Fig. 1';

Fig; his a. section taken along the line 4-4 0! pound discarded. This tool removes all or the Fig.1;-

Fig. is a section taken along the line 5--5 of Fig. 2;

Fig. 6 is a view taken along the line 6-6 of Fig. l and shows a cut-away section along the line 8'6 of Fig. 5;

Fig. '7 is a section taken along the line of 11 of i 6;

Fig. 8 is an exploded perspective showing the construction of and operational relationship between the body member and thimble comprising part of the head end of the tool of Fig. 1; and

Fig. 9 illustrates the preferred manner of applying the invention to remove compound from a row of terminals on a line finder or selector terminal bank of a panel switching system.

Referring to Fig. 9 the removing tool is seen to comprise a container I having attached there- 29. This heating element 29 is energized from a suitable source of electrical power by way of conductors 36, which for convenience may be h cated within the air hose 4 as shown.

On the top or container I is an exhaust deflector 5 conveniently attached to flanged ring 32 which in turn is adapted to be removably attached to the top of container l by means of set screw 33 or other detent arrangement or a cotter pin type of device. The effect of this arrangement is to provide that deflector 5 may be suitably positioned with reference to the operator of the machine such that the exhaust gases do not come forth at an unreasonble proximity to said operator. Reference is made to Fig. 9 wherein it is seen that for a right-handed operator the deflector 5 may be arranged as shown to a bottom section I2 by means of a threaded interconnection and a handle 2 by means of angle members 2%. Near the top of container I is situated a connector 3 by means of which an air hose I may be attached to the container I. An exhaust vent or deflector 5 is attached to the top of container I. Situated at the side of container I is a wooden hand grip 6 whichhouses apparatus to be described later. Extending from the end of this hand grip 6 are pipes 7 and 3 extending to a head end 9 of the removing tool. It is seen in Fig. 9 that an operator is em- Dloying the removing tool to remove compound from a row of terminals on a terminal bank such as it) of well-known type as found for-instance in the panel telephone switching system. It is also seen that the tool is designed so as not to interfere with the brush rod H, a well-known part of such a switch.

Referring in more detail to Fig. 1, the bottom section or can I2 is attached to the container I by means of screw threads IS. The can I2 is adapted to contain absorbent material I4 such as cotton or like material. Situated between the can I 2 and the main container I is a coarse mesh screen I5. Directly above the screen I5 is a conical sieve-like member it having holes I! and I8 therein as indicated. A pipe-like member I9 is seen to protrude into the container I through the top of the conical member [6. This pipe-like member I9 extends through the hand grip 6 and protrudes from the end thereof in order to have the pipe 8 from head 9 attached thereto by means of coupling 29. In the vicinity of the top of the conical section I8 is a fine mesh screen 23 held in position by means of a framework ZI which in turn is held to the container I by means of brackets 22. In this regard reference is made to Fig. 4.- which is a sectionalized view taken along the line 4-4 of Fig. 1 and shows a plan view of the screen 23 held by means of framework 2 I, comprising radial arms 25, circumscribed about pipe I9 and held to the container I by means of brackets 22. .The fine. screen 23 is adapted to hold on the top thereof a suitable quantity of activated carbon 24. 1

Handle 2 is attached to the container I by means of angle members 26 as previously mentioned. In addition near the top of container I is a pipe fitting 3 which is adapted to receive fitting 3| on the end of an air hose 4 extending from a suitable source of pressurized air. A pipe-like'member 27 extends from the pipe fitting 3 through the container I and through the hand grip E to the end of the hand grip B where the pipe 27 is attached to pipe 7 by means of fitting 28. .Within the pipe member 27, and within the hand grip 6, is an electrical heating element to deflect the exhaust gases away from the 'operator.

For a better understanding of the nature of the hand grip 6 and the location of the pipes l9 and 21 located therein, reference is made to Fig. 3. It is seen that hand grip 6 is constructed in two similar sections which are held together about the pipes 2'! and I9 by means of bolts 35 and 36. It is also to be pointed out that the electrical heating element 29 located within pipe member 21 is arranged to provide a passageway 34 therethrough whereby the air under pressure from air hose 5 may freely pass to pipe 1 on end 9 of the tool. Likewise 37 designates the nature of the cross-section of pipe [9.

Ihe head end 9 of the tool which rigidly houses pipes I and 8 is adapted as shown in Fig. 2 to engage a row of terminals such as 38 and is also adapted so as not to interfere with brush rod II. It is seen that when the head Qengages the row of terminals 33, pipes 1 and 8 have sufficient clearance with reference to brush rod II so as not to interfere therewith. It is common practice in this type of telephone system, namely, the panel type, that the rows of terminals such as 38, 39 and 4% are arranged either as tip, sleeve and ring, respectively, or ring, sleeve and tip, respectively, and that in the use of such a preservative compound as we are interested with here. the sleeve terminals 39 are not required to be so covered. Because of this it is not necessary, of course, to remove material from the row of terminals 39 which incidentally would be impossible because of the position of the brush rod H.

The remaining description is directed in detail to the structural features of the head end 9 and reference is made to one or more of Figs. 5 to 8, inclusive.

With reference to Fig. 5 in particular, the pipe 8 is seen to be attached to a body member 41 by means of sweat soldering or other suitable means. This body member 41 is shown in perspective in Fig. 8 and continuous reference is suggested to this perspective for a clear visualization of the structural features about to be described. Pipe I, which is previously described as the inlet pipe for the pressurized air, is screw fitted into a metallic member M and has a suitable opening in the end thereofby means of which the air may escape into passageway d3 of the metallic member ii. A suitable machine screw 44 is adapted to engage the opening 43 by means of a tapped hole in the top thereof whereby cleaning of this opening is is facilitated when necessary. Secured by means of screws 42 to metal member 4| on either side of the head 9 is an insulator piece 59. A slot or groove is provided in the end of this insulated piece 59 for accommodating a row. of terminals sucha's is as is eilie has a suitable slot therein, as does the body member 41 and the insulator 59, for accommodating a row of terminals. Located between slots '51, for' in'stance, on the left side ofthe body member ofFig. 6, is another-slot' l which does not connect to the circumferential groove atbut doesopenu-pon the end of the body which is covered by the thimble 46. Thisslot 54 has a narrow slit r slot 49 in it to connect said slot 54 with the inner bore of: the. body 41'. On the end of the body 41 is a beveled surface 51 which, in cooperation with the thereto abutting ends 58 of the thimble, comprises a transverse passageway whereby air under pressure in slots mustbe changed; in direction at the open end of slot EM and consequently be forced through the narrow slit or slot 49, and likewise 48* on the other side of the body, to the inner bore of the body in the direction of the arrows 55 of Fig. 7.

With reference to Fig. 7 the passagewayd esignated as 52 is the-one previously referred to, as being formed between the beveled edge 51 of the body member 4-? and the thereto abutting end 58 of the thimble. It is also to be noticed that the cars 53 of the thimble are tightly fitted against the inner beveled surfaces 653 of the body to provide a backward slanting surface against which the air under pressure may be guided in the direction of the arrows 55. The terminal 38 in Fig. 7 is shown in a representative position which, as will be appreciated, will permit the stream of air illustrated by arrows E5 to sweep across the sur face of the terminal 38 forcing the compound from these surfaces back into the exhaust pipelike member 8 in the direction of the arrow 56. It is noticed in Fig. 6 that the narrow slits or slots 48 and 49 in respective sides of the body 47 are not opposite each other. They are displaced vertically so that the respective stream of air will not interfere with each other.

Returning now to Fig. 1, it will be recalled that reference was made to an electrical heating element 29 through which the air was required to pass in its travel to the head 9. It is necessary to preheat this air in order to make the compound become fluid for ease of removal by the stream of air. This compound assumes a consistency similar to that of Vaseline at room temperature and requires application of heat before it will become fluid.

The exhaust products are forced through the pipe 8 and into the pipe is and impinge upon the coarse screen it above the can 12 in the bottom of container 1. The heavier constituents of these exhaust products, being mostly globules of compound, will be forced through the coarse screen l5 and will be absorbed by the absorbent material [4. The gaseous constituents of the exhaust products will be deflected as indicated by the arrows within the conical member l6 and will escape through holes I! or I8 or both to be filtered through the activated carbon 24 suspended on the fine mesh screen 23. The activated carbon, as is well known, has the ability to remove certain obnoxious gases and as a result the exhaust gases which are excluded by the deflector 5 will not be 6. injurious to operators or ether pe'rsiiririei the vicinity.

The utility of this-tool i'srepreserited by several features which ma now be readily appreciated, a few of which are summarized'asfollows} By" virtue of the air under iiressure being deflected by the air directing end structure across the s'ur faces of the terminals and by virtue of itsbeing; preheated, practically all of the compounded the terminals, and as sit-matter o'f-fact'on all other parts of the terminal 1 bankin the close vicinity th'eretais removed into the container then: separates gaseous and solid exhaust particles, confines the" solid particles and filters: the'gaseous components whereby none of the gas products: injurious to parse nel' or equipment are allowed tog 'o tree. In addition it' i's pointed outxthat-to operate this machine requires no particular. skill upcn-tnepartof theop'erator in that it isinecessary for the operator m'erelyto'engag'ethe-toot with a row of terminals and allow the: tool:toi drop by its own weight and therebyaccomplish' itsjob. The operator is merely required to guide the tool'such that it will not bend orotherwisedi'sfigure-the row of terminals.

Anysuitablesupply of pressurized" air and electricity, as previously indicated 1 were rieces: sary, may be adapted for use with .thisgdevice'. It; is tobe pointed out in connection;w'ithther-heats ing element that it is advisable ,to-combine elcce trical switching of the heating element with the pressure of the air and passage thereof through the tube 21 in order that excessive heat will not be generated unless a suitable quantity of air is passing through the heating element to thereby relieve same of too much heat, which as will be appreciated may injure various components of this machine. With reference to Figs. 6 and 7 it will be noticed that the insulator member 59 is suitably dimensioned in the slot or groove in the end thereof and in its projection beyond the end of the body 41 such that only insulating material may come in contact with terminals or terminal banks. This feature is provided in order that one may operate this device whether or not the terminals are energized by electric power.

Many modifications may be made to the structure or to the application of the principles disclosed in the structure without departing from the spirit of my invention and I therefore append claims which alone define the scope of my invention.

What is claimed is:

l. A tool for removing petrolatum compound from the terminals of a panel switch bank comprising a head having a grooved portion of electrically insulating material, an inlet pipe connected to said head for conducting air under pressure to said head, an exhaust pipe, and a bifurcated air directing structure in said head connected to said exhaust pipe, the inwardly facing sidewalls of said bifurcated structure being fitted into and aligned with the sidewalls of said groove such that all of the said walls define a channel which is adapted to embrace a row of said terminals, such structure having narrow slots in the sidewalls thereof connected by passageways to the said inlet pipe and having bafiie surfaces for directing within the said structure streams of pressurized air through said slots and across said terminal surfaces over which said head is moved and into said exhaust pipe after said streams of air have traversed the said surfaces of said terminals to thereby remove said 7 compound from said terminals into said exhaust pipe.

2. A tool for removing petrolatum compound from theterminals of a panel switch bank comprising a head having a grooved portion of electrically insulating material, an inlet pipe connected to said head for conducting air under pressure to said head, anrexhaust pipe, and a bifurcated air directing structure in said head connected to said exhaust pipe, said structure comprising a bifurcated cylindrical body member having the inwardly facing sidewalls thereof fitted into and aligned with the sidewalls of said groove such that all of the said walls define a channel which is adapted to embrace a row of said terminals, said body member having a central bore connected with said exhaust pipe and having first passageways extending from a connection with said inlet pipe to the bifurcation end of each divided portion of said member and having further passageways extending from the bifurcation end of each portion of said body member and communicating through narrow slots with the inner bore of said member and having a bifurcated thimble snugly surrounding said body member, said thimble having a baffle on each bifurcation end portion thereof for reversing the direction of the air streams entering through said first passageways and diverting them within said structure through said further 8 passageways and said slots and across the sur'- faces of said terminals into said outlet pipe.

3. A tool for removing petrolatum compound from the terminals of a panel switch bank as set forth in claim 2, wherein the inlet pipe contains a heating element for heating said pressurized air to enable same to render the compound fiuid to facilitate the removal thereof from said terminals and wherein the exhaust pipe is terminated in filtering means to remove solid waste products from the exhaust air and to remove obnoxious gaseous waste products from said exhaust air prior to the expulsion of said air from said tool.

VICTOR F. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

Stewart Sept. 1'7, 1946 

